Abstract The Antillean manatee occurs discontinuously from the state of Amapá to the state of Alagoas on the coast of Brazil. There is also evidence of reintroduced manatees using the coasts of Sergipe and Bahia, with a preference for calm shallow waters. This study characterized the home range areas of six rehabilitated manatees released in northeastern Brazil. The activities were conducted in the states of Paraíba, Sergipe, and Bahia. Type of environment, substrate, depth, aquatic vegetation, physicochemical variables of the water, presence of solid waste, human settlements, and watercraft were considered to characterize the areas. The results showed a manatee preference for sheltered areas. Resources were available in larger quantities in the dry season, and a reduction in the availability of food items was fund over the years. High overlap was found in the multivariate space of the individuals in terms of the characteristics of the habitats. The estuary of the Paraíba River and the coastal area of Cabedelo Beach in Paraíba showed the greatest amount of solid waste, human settlements, and watercraft. Released manatees exhibited a preference for sites shallower than two meters, with food resources and fresh water availability. Brazil Bahia waters environment substrate depth vegetation waste settlements season years habitats meters

Abstract The inadequate choice of a diagnostic method or the option for techniques that have low sensitivity and specificity may limit the diagnosis of parasitic agents that affect aquatic mammals. The aim of this study was to evaluate the performance of the FLOTAC technique and compare it with three traditional methods (Willis, sedimentation and centrifugation- flotation) used in the diagnosis of gastrointestinal parasites in aquatic mammals. For this, 129 fecal samples from 12 species were collected. Each sample was submitted to laboratory processing using the Willis, Hoffman techniques, Faust method and FLOTAC. Sensitivity, specificity, real prevalence, estimated prevalence, positive predictive value, negative predictive value, correct classification (accuracy) and incorrect classification were evaluated to compare the different diagnostic methods. The highest frequency of positive samples occurred using FLOTAC (46.51%), compared to Hoffman (23.25%), Faust (10.07%) and Willis techniques (6.97%). In the samples analyzed, the occurrence of Strongylidae eggs and Eimeriidae oocysts was frequently observed. The FLOTAC technique proved to be the most appropriate technique and due to its efficacy, is strongly recommended for coproparasitological evaluations in aquatic mammals.

Abstract: The West Indian (Trichechus manatus) and Amazonian (T. inunguis) manatees have a sympatric occurrence at the mouth of the Amazon River. A result of this interspecific encounter is the occurrence of hybrids, which are frequently found along the coasts of Amapá state in Brazil, French Guiana and Guyana. Here we present new genetic evidence indicating the occurrence of a hybrid swarm along the Guianas Shield coastline, which is an interspecific hybrid zone that also separates T. manatus populations located east (Brazil) and west (Caribbean, Gulf of Mexico, Florida and Antilles). In addition, we suggest that this hybrid population occupies a peculiar mangrove-rich environment under strong influence of the Amazon River plume, which requires an independent management and should be considered a special conservation area.

SUMMARY: This study aimed to characterize the structures of the posterior respiratory system of two species of river dolphins: Inia geoffrensis and Sotalia fluviatilis. The respiratory tract of both species was evaluated using macro and microscopic techniques. Four macroscopic anatomical structures were identified: Trachea, main bronchus, tracheal bronchus and lung. The presence of the exuberant tracheal bronchus suggested ease of gas exchanges. Histological analysis revealed the presence of alveolar ducts and myoelastic sphincter in these Amazonian cetaceans. The posterior respiratory portion of the Amazonian dolphins presents similarity with other odontocetes and the knowledge of this structure can also help contribute to the understanding of the physiology of diving and how these species are adapted to their habitat.

RESUMEN: Este estudio tuvo como objetivo caracterizar las estructuras del flujo respiratorio de dos especies de delfines de agua dulce: Inia geoffrensis y Sotalia fluviatilis. Los tractos respiratorios fueron estudiados con las técnicas de evaluación macroscópica y microscópica. En ambas especies se identificaron cuatro estructuras anatómicas macroscópicas: tráquea, bronquios principales, bronquio traqueal y los pulmones. La presencia de un bronquio traqueal exuberante sugiere un aumento en el intercambio de gases y el aumento de tiempo de inmersión de las especies. El análisis histológico reveló la presencia de los conductos alveolares, y del esfínter mioelástico en los cetáceos amazónicos. La porción respiratoria posterior de los delfines del Amazonas tiene similitud con otras ballenas dentadas y su conocimiento puede contribuir a la comprensión de la fisiología del buceo y a como estas especies están adaptadas a su hábitat.

RESUMO Em uma região particular da Amazônia ocidental, peixes-boi amazônicos (Trichechus inunguis) vivem em um ambiente que se torna inóspito para eles durante a água-baixa anual. Para fugir dele, realizam uma migração perigosa para o refúgio enquanto o nível da água desce rapidamente. Nosso objetivo foi compreender melhor o papel da variação da profundidade neste processo migratório. Analisamos os únicos dados de rastreamento de peixes-boi selvagens (n=10 machos), 30 anos de imagens Landsat, 14 anos de hidrógrafa e um modelo batimétrico 3-D. As rotas migratórias possuíam trechos mais rasos, denominados gargalos migratórios, que secaram no final da maioria das vazantes, bloqueando o acesso ao refúgio. Os peixes-boi começaram a migração em tempo justo para atravessar os gargalos mais distantes, sugerindo que a sintonizaram para maximizar o período se alimentando sem comprometer a segurança. Para tal, parecem ter estimado a profundidade nos gargalos. Adicionalmente, um gargalo foi criado em <15 anos, ilustrando o dinamismo do ambiente e o desafio que isto impõe aos peixes-boi. Esses resultados provavelmente valem para boa parte da área de distribuição da espécie. Argumentamos que peixes-boi possuem um mapa cognitivo atualizável do ambiente e são comportamentalmente plásticos. Os planos de construção de barragens hidrelétricas, se concretizados, criariam mais gargalos e regimes de inundação menos previsíveis, dificultando a migração e consequentemente aumentando a mortalidade de peixes-boi. Também particionariam a espécie em populações pequenas, vulneráveis à extinção no curto-prazo. O desfecho seria o segundo colapso da espécie. O crescimento econômico não deve vir às custas da extinção do icônico peixe-boi.

ABSTRACT In a particular region within western Amazonia, Amazonian manatees (Trichechus inunguis) live in a floodplain environment that becomes inhospitable for them during the annual low-water season. To flee from it, they undergo a dangerous migration to a refuge while water levels are dropping fast. Our aim was to better understand the role of depth variation in this migratory process. We analyzed the sole tracking data on wild manatees (n=10 males), 30 years of Landsat images, a 14-year hydrograph and a 3-D bathymetric model. Migratory routes contained shallower segments, here called 'migratory bottlenecks', which dried out at the end of most lowering-water seasons, blocking the passage to the refuge. Manatees began migrating just in time to traverse the bottlenecks furthest away, suggesting they fine-tuned their departure so as to maximize time within the foraging home range without compromising safety. They apparently achieved this by estimating depth at the bottlenecks. Moreover, a bottleneck was created in >15 years, illustrating the environment's dynamism and the challenge this imposes upon manatees. Our results are probably generalizable to most of the species' range. We contend manatees possess an updatable cognitive map of their environment and are behaviorally plastic. Current dam-building plans, if implemented, would create more bottlenecks and make flooding less predictable, increasing manatee mortality from unsuccessful migrations. It would also partition the species into small populations, each prone to short-term extinction. The natural outcome would be the second species-level collapse. Economic growth should not come at the expense of the extinction of the iconic manatee.

A caça comercial foi determinante para o desaparecimento de ariranhas em áreas de sua ocorrência histórica na Amazônia brasileira. Depois de cerca de trinta anos de ausência, ariranhas foram avistadas no lago Amanã em 2000, após a criação da Reserva Amanã. Ao longo de quatro anos foram conduzidas expedições a campo com o objetivo de confirmar e quantificar a presença de ariranhas e avaliar ameaças locais. Informações acerca do impacto humano sobre essa população foram compiladas a partir de entrevistas com 83 moradores. Áreas de sobreposição utilizadas tanto pela ariranha quanto pelo homem resultaram em interações negativas. As ameaças identificadas incluem: percepção dos moradores locais em relação à espécie como concorrentes da pesca de subsistência, conversão de áreas naturais em culturas anuais, remoção de filhotes para manutenção como animais de estimação e potencial transmissão de doenças por animais domésticos. Mitigação e monitoramento dessas ameaças são de extrema importância para a manutenção das ariranhas na área.

Commercial hunting was determinant in the disappearance of giant river otters along areas of historical occurrence in the Brazilian Amazonia. After approximately 30 years of absence, giant otters were spotted in the Amanã Lake in 2000, after the creation of the Amanã Reserve. Four years of field surveys were carried out to confirm the presence of giant river otters in the area and to assess local threats to the species. Information on the human impact on this otter population was compiled based on 83 interviews with residents. Areas of overlap used by both otters and humans resulted in negative interactions. The identified threats included: perception of otters as competitors for subsistence fisheries; conversion of natural areas into annual crops; removal of cubs to be raised as pets; and potential disease transmission from domestic animals. Mitigation and monitoring of these threats are paramount for the maintenance of giant river otters in the area.

La caza comercial fue determinante para la desaparición del lobo de río a lo largo de su área de ocupación histórica en la Amazonía brasilera. Después de casi 30 años de ausencia, lobos de río fueron observados en el Lago Amanã en el año 2000, después del establecimiento de la Reserva Amanã. Nuestro equipo desarrolló un estudio de campo de cuatro años con el objetivo de confirmar y cuantificar la presencia de la especie y de levantar las amenazas locales. Informaciones acerca del impacto humano sobre esta población fueron compiladas a partir de entrevistas con 83 habitantes. Áreas de superposición usadas por el lobo de río y el hombre resultan en interacciones negativas. Las amenazas identificadas incluyen: (1) percepción de los lobos de río como competidores en la pesca de subsistencia; (2) conversión de áreas naturales en áreas de cultivos anuales; (3) retiro de crías para ser criadas como mascota; (4) transmisión potencial de enfermedades por animales domésticos. La mitigación y el monitoreo de esas amenazas son de suma importancia para la conservación del lobo de río en la región.

O objetivo deste trabalho foi descrever curvas de crescimento para peixes-boi-da-Amazônia de vida livre no Brasil. Foram utilizados dados etários e biométricos de 60 peixes-boi-da-Amazônia, 33 machos e 27 fêmeas, capturados entre 1993 e 2006 por pessoas ribeirinhas do médio Solimões e do Rio Pirativa, na região Amazônica, oriundos do Instituto de Desenvolvimento Sustentável Mamirauá e do Centro Nacional de Conservação e Manejo de Mamíferos Aquáticos/ICMBio. O modelo matemático não-linear utilizado para análise desses dados foi a equação derivada de von Bertalanffy, sendo calculadas duas equações de crescimento, uma para os machos L(t)macho = 299,4[1-e-0,0897507(t+6,55696)], e outra para as fêmeas L(t)fêmea = 256,1[1-e-0,23731(t+ 3,01921)]. Com o desenvolvimento dessas equações, o comprimento do peixe-boi-da-Amazônia ao nascer foi de 133,2 cm (média = 113,0 cm; SD = 34,4 cm) quando macho, e 131,0 cm (média = 124,7 cm; SD = 22,0 cm) quando fêmeas. Nos machos a taxa de crescimento anual obtida foi de 0,09 cm (IC 95%: ± 0,002), atingindo uma envergadura máxima de 299,4 cm (IC 95%: ± 2,039), enquanto as fêmeas apresentaram uma taxa de crescimento de 0,24 cm ao ano (IC 95%: ± 0,004), podendo alcançar até 256,1 cm (IC 95%: ± 0,4832) de envergadura. Apesar da equação de von Bertalanffy não ser comumente utilizada para sirênios, e quando aplicada anteriormente não ter obtido resultados satisfatórios, neste estudo apresentou-se adequada para a elaboração da curva de crescimento para peixe-boi-da-Amazônia de vida livre.

The objective of this work was to describe growth curves for free-ranging Amazonian manatees in Brazil. Data analyzed included age estimates and biometrics from 60 Amazonian manatees (33 males and 27 females) captured between 1993 and 2006 by local residents of the mid-Solimões and Pirativa Rivers, in Amazonia, and collected by the Instituto de Desenvolvimento Sustentável Mamirauá and Centro Nacional de Conservação e Manejo de Mamíferos Aquáticos/ICMBio. The non-linear mathematical model used to analyze the data was the von Bertalanffy's equation; two growth curves were calculated, one for males L(t)male = 299.4[1-e-0.0897507(t+6.55696)], and one for females L(t)female = 256.1[1-e-0.23731(t+ 3.01921)]. Based on these equations, length at birth for the Amazonian manatee is estimated at 133.2 cm (average = 113.0 cm; SD = 34.4 cm) for males, and 131.0 cm (average = 124.7 cm; SD = 22.0 cm) for females. Among the males, the annual growth rate was 0.09 cm (95% CI: ± 0.002), with a maximum length of 299.4 cm (95% CI: ± 2.039), while females presented a growth rate of 0.24 cm per year (95% CI: ± 0.004), reaching up to 256.1 cm (95% CI: ± 0.4832) of total length. Even though von Bertalanffy's equation is not commonly used for sirenians, and considering that when previously applied it did not obtain satisfactory results, in this study it proved adequate for the establishment of the growth curve for free-ranging Amazonian manatees.